Vehicle air conditioner

ABSTRACT

A vehicle air conditioner comprises: a case  21  that is disposed in an interior-cabin space  15  formed in a cabin  10  and that forms an air passage through which air flows; and a heat exchanger  24  that is accommodated in the case  21  and that exchanges heat with the air, wherein the case  21  is disposed adjacent to a surrounding wall section  12  of the cabin  10 , a case side opening  40  that is opened and closed by a case side cover  41  is formed in a region of the case  21  adjacent to the surrounding wall section  12 , the case side opening  40  overlaps a cabin side opening  42  that is provided in the surrounding wall section  12  and that is opened and closed by a cabin side cover  43 , and a heat exchange core section  24   a  of the heat exchanger  24  faces the case side opening  40 . Therefore, the heat exchanger  24  can be inspected and cleaned from the outside of the cabin  10  while the heat exchanger  24  remains accommodated in the case  21 , and thus, the heat exchanger  24  of the vehicle air conditioner can be inspected and easily cleaned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a vehicle air conditioner that is preferably used in a construction machine such as a hydraulic excavator, etc.

2. Description of the Related Art

Conventionally, in a vehicle air conditioner, a cooling heat exchanger (an evaporator) is accommodated in the case of an interior-cabin air conditioning unit, and when inspected and cleaned (maintained), the cooling heat exchanger has to be inspected and cleaned in a narrow interior-cabin space after taking it out from the case of the air conditioning unit. As a result, it takes a great deal of time to inspect and clean the cooling heat exchanger.

Therefore, a cooling heat exchanger in a vehicle air conditioner that can be inspected and cleaned in a short period of time is proposed in Japanese Unexamined Utility Model Publication No. H05-56516. In the prior art, in a vehicle such as a truck, for example, in which the air conditioning unit is disposed immediately rearward of a front shell plate of the vehicle, both a front side of the case of the air conditioning unit and the front shell plate of the vehicle are provided with respective overlapping openings for taking out the cooling heat exchanger so that respective covers covering openings can be opened and closed.

Therefore, when the cooling heat exchanger is inspected and cleaned, first, both covers are opened, and then, the cooling heat exchanger is removed from the case of the air conditioning unit through both openings to the forward (outside) of the vehicle.

Thus, in this prior art, the cooling heat exchanger is removed to the outside of the vehicle, and therefore, removing the cooling heat exchanger in a narrow interior-cabin space does not have to be performed, which results in reduced time for inspecting and cleaning of the cooling heat exchanger.

However, in the prior art described above in which the cooling heat exchanger is removed from the case of the air conditioner unit, it takes time and effort to remove refrigerant pipes from the cooling heat exchanger. Further, it also takes time and effort to drain refrigerant from the vehicle air conditioner before removing the refrigerant pipes.

In particular, in a construction machine such as a hydraulic excavator, which is used in a sandy or dusty environment, etc., a heat exchange core section of the cooling heat exchanger may become clogged due to dust adhering to the clearance between the fins of the cooling heat exchanger. Therefore, the cooling heat exchanger has to be inspected and cleaned more frequently, and as a result, the above problem becomes more complicated.

Further, the above problem not only occurs in the cooling heat exchanger, but also in a heating heat exchanger.

SUMMARY OF THE INVENTION

In view of the above problem, it is an object of the present invention to provide a vehicle air conditioner in which a heat exchanger can be inspected and easily cleaned.

In order to achieve the above object, according to the present invention, there is provided a vehicle air conditioner comprising:

a case (21) that is disposed in an interior-cabin space (15) formed in a cabin (10) and forms an air passage through which air flows; and

a heat exchanger (24) that is accommodated in the case (21) and exchanges heat with the air,

wherein the case (21) is disposed adjacent to a surrounding wall section (12) of the cabin (10),

a case side opening (40) that is opened and closed by a case side cover (41) is formed in a region of the case (21) adjacent to the surrounding wall section (12),

the case side opening (40) overlaps a cabin side opening (42) that is provided in the surrounding wall section (12) and is opened and closed by a cabin side cover (43), and

a heat exchange core section (24 a) of the heat exchanger (24) faces the case side opening (40).

In this vehicle air conditioner, the heat exchange core section (24 a) of the heat exchanger (24) can be exposed to the outside of the cabin (10) by opening the case side opening (40) and cabin side opening (42).

In other words, the heat exchange core section (24 a) of the heat exchanger (24) can be inspected and cleaned from the outside of the cabin (10) while the heat exchanger (24) remains accommodated in the case (21).

Therefore, when the heat exchanger (24) is inspected and cleaned, the heat exchanger (24) does not have to be taken out from the case (21). Further, the heat exchanger (24) does not have to be inspected and cleaned in the narrow cabin (10). As a result, the heat exchanger (24) can be inspected and easily cleaned.

When the heat exchanger (24) is inspected and cleaned, the case side opening (40) and the cabin side opening (42) can be closed by the case side cover (41) and the cabin side cover (43), and therefore, the case side opening (40) does not impede air passing through the case (21) and the cabin side opening (42) does not limit cabin space of the cabin (10) (i.e. interior-cabin space (15)).

In the vehicle air conditioner according to the present invention, specifically, an air flow upstream portion of the heat exchange core section (24 a) faces the case side opening (40), and therefore, the air flow upstream portion of the heat exchange core section (24 a) that is more likely to be covered with dust can be inspected and easily cleaned.

Further, in the vehicle air conditioner according to the present invention, specifically, the surrounding wall section is a rear wall section (12) of the cabin (10),

the case (21) is disposed rearward in the cabin (10), and

the heat exchanger (24) is disposed rearward in the case (21).

Therefore, the heat exchanger (24) can be inspected and cleaned from the rearward of the cabin (10).

Still further, in the vehicle air conditioner according to the present invention, specifically, an area of the case side cover (41) is smaller than that of the cabin side opening (42),

the case side cover (41) is removably attached to the case (21), and

the case side opening (40) is opened and closed when the case side cover (41) is attached and removed, respectively.

The case side opening (40) is then opened and closed when the case side cover (41) is attached and removed, respectively, and therefore, the opening/closing structure of the case side opening (40) can be simplified.

Still further, an area of the case side cover (41) is smaller than that of the cabin side opening (42), and therefore, the removed case side cover (41) can be removed to the outside of the cabin (10) through the cabin side opening (42). Therefore, the removed case side cover (41) does not interfere with the inspection and cleaning of the heat exchanger (24).

Still further, in the vehicle air conditioner according to the present invention, specifically, an area of the case side cover (41) is smaller than that of the cabin side opening (42),

the case side cover (41) is swingably supported with respect to the case (21) in a direction orthogonal to the opening direction of the case side opening (40),

the case side opening (40) is opened and closed by swinging the case side cover (41), and,

further, when the case side cover (41) is swung in a direction to open the case side opening (40), the case side cover (41) may protrude to the outside of the cabin (10) through the cabin side opening (42).

Therefore, the case side opening (40) can be easily opened and closed by the case side cover (41).

Still further, in the vehicle air conditioner according to the present invention, specifically, the case side cover (41) is supported and can be shifted with respect to the case (21) in a direction orthogonal to the opening direction of the case side opening (40),

the case side opening (40) is opened and closed by translating the case side cover (41), and,

further, the case side cover (41) may be shifted in the interior-cabin space (15).

The reference numerals in parentheses affixed to the means set forth in this section correspond to the specific means set forth in embodiments described below.

The present invention may be more fully understood from the description of the preferred embodiments of the invention, as set forth below, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic cross-sectional view of a cabin of a hydraulic excavator according to a first embodiment of the present invention;

FIGS. 2A and 2B are a plan view and rear view, respectively, of an air conditioning unit shown in FIG. 1;

FIG. 3 is a cross-sectional view taken along the line A-A in FIG. 2B;

FIG. 4 is a schematic cross-sectional view of a cabin of a hydraulic excavator according to a second embodiment of the present invention; and

FIG. 5 is a schematic cross-sectional view of a cabin of a hydraulic excavator according to a third embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIGS. 1-3 show a first embodiment of the present invention, in which a vehicle air conditioner according to the present invention is applied to a construction machine, or more specifically, a hydraulic excavator. FIG. 1 is a schematic cross-sectional view of a cabin (an operator's cage) of a hydraulic excavator according to this embodiment; FIGS. 2A and 2B are a plan view and rear view, respectively, of an air conditioning unit in FIG. 1; and FIG. 3 is a cross-sectional view taken along the line A-A in FIG. 2B. In FIGS. 1-3, arrows marked with “Front”, “Rear”, “Top”, “Bottom”, “Left” and “Right” designate respective directions in the cabin.

A cabin 10 of a hydraulic excavator has a surrounding wall section comprised of a front wall section 11, a rear wall section 12, a ceiling wall section 13, a floor wall section 14 and left and right side wall sections (not shown), and the cabin 10 forms an interior-cabin space 15 surrounded by the surrounding wall section. An upper part of the front wall section 11 is comprised of a front windshield 16 and an upper part of the rear wall section is comprised of a rear windshield 17. At least one of the left and right side wall sections is provided with an operator's door (not shown).

A seat 18 on which the operator of the hydraulic excavator sits is disposed substantially in the center of the floor section 14. An air conditioning unit 20 is disposed at a position rearward and downward from the seat 18, i.e., at a rearmost and downmost position of the interior-cabin space 15. It should be noted that the shape of the air conditioning unit 20 is shown in a simplified manner in FIG. 1 for convenience of illustration.

Next, a specific configuration of the air conditioning unit 20 will be described. The air conditioning unit 20 has a box-shaped case 21 and an air passage through which air flows is formed inside the case 21.

The case 21 is molded of a resin material such as polypropylene that has elasticity to some extent and excellent strength wherein the case 21 is molded with a plurality of divided cases for convenience of molding. Then, the case 21 is constructed by integrally fastening the plurality of divided cases by using fastening means such as screws, metal spring clips and the like.

In this example, a blower section 22 is integrally disposed on the side wall section of the case 21. This blower section 22 has a centrifugal blower fan 22 b that is rotated by a motor 22 a, and a scroll casing 22 c that accommodates the blower fan 22 b.

A rotational axis (not shown) of the blower fan 22 b is disposed vertically, and therefore, an air inlet section 22 d of the blower section 22 is disposed on a top surface section of the scroll casing 22 c. An air outlet section 22 e of the blower section 22 is opened rearward of the scroll casing 22 c (downward in FIG. 2A) toward the case 21 (the right side in FIG. 2A).

An inside/outside air switching box 23 for switchably introducing inside and outside air is disposed on a top surface section of the blower section 22. The inside/outside air switching box 23 is provided with an outside air introduction opening 23 a formed on a rear wall section thereof and the outside air introduction opening 23 a is opened and closed by an outside air door (a plate-like door, not shown). On the other hand, the inside/outside air switching box 23 is also provided with an inside air introduction opening 23 b formed on a front wall section thereof and the inside air introduction opening 23 b is opened and closed by an inside air door (a plate-like door, not shown).

In this example, an electric actuator comprising a servo motor (not shown) is used as a driving mechanism for rotating the outside air door and the inside air door. Alternatively, as the driving mechanism for the outside air door and the inside air door, it may be possible to use a manual operation mechanism for transferring manual operating force of an inside/outside air switching operation member (for example, a manual operation lever) provided on an air conditioner operation panel (not shown) to respective rotational axes of the doors via a cable, a link mechanism and the like.

In an outside air introduction mode, the outside air door is operated to a position where the outside air introduction opening 23 a is fully opened and the inside air door is operated to a position where the inside air introduction opening 23 b is fully closed. Therefore, the outside air is introduced into the inside/outside air changing box 23 from the outside air introduction opening 23 a via an outside air port and an outside air duct (not shown).

On the other hand, in an inside air introduction mode, the outside air introduction opening is operated to a position where the outside air introduction opening is fully closed and the inside air door is operated to a position where the inside air introduction opening 23 b is fully opened. Therefore, the inside air is introduced into the inside/outside air changing box 23 from the inside air introduction opening 23 b.

Further, in an inside/outside air introduction mode, both the outside air door and the inside air door are operated to the positions where the outside air introduction opening 23 a and the inside air introduction opening 23 b are fully opened. Therefore, the outside and inside air is introduced into the inside/outside air changing box 23 from the outside air introduction opening 23 a and the inside air introduction opening 23 b.

At a rearward position in the case 21 (in a rightward position in FIG. 3), a substantially rectangular-shaped cooling heat exchanger 24 is disposed substantially vertically across the entire length of the case 21. Therefore, an inflow space 25 is formed between the cooling heat exchanger 24 and a rear wall section 21 a of the case 21 and the air (the inside/outside air) sent from the air outlet section 22 e of the blower section 22 toward the case 21 flows into the inflow space 25.

Therefore, the whole of the air (the inside/outside air) flowing into the case 21 from the air outlet section 22 e of the blower section 22 passes through the cooling heat exchanger 24 after the inflow space 25 as indicated by arrow a.

The cooling heat exchanger 24 is an evaporator in a refrigeration cycle that has a heat exchange core section 24 a comprising: a plurality of tubes through which a refrigerant passes; and fins that are joined to outer surfaces of the tubes. As air passes through clearance in this heat exchange core section 24 a, the cold low-pressure refrigerant in the refrigeration cycle absorbs heat from the passing air and evaporates to cool the air.

The cooling heat exchanger 24 in this example has, at its top and bottom ends, tank sections 24 b for distributing or collecting the refrigerant into/from the plurality of tubes.

A compressor (not shown) for circulating the refrigerant in the refrigeration cycle is driven by an engine (not shown) of the hydraulic excavator via an electromagnetic clutch.

Inside the case 21, a substantially rectangular-shaped heating heat exchanger 26 is disposed at the air flow downstream (vehicle forward) of the cooling heat exchanger 24 and at the bottom side of the case 21. The heating heat exchanger 26 is disposed across the entire width of the case 21.

The heating heat exchanger 26 is a hot water heat exchanger that heats the air by using cooling water (hot water) for the engine of the hydraulic excavator as a heat source and that has a heat exchange core section 26 a comprising: a plurality of tubes through which the hot water passes; and fins that are joined to outer surfaces of the tubes. As the air from a heater passage 36 passes through clearance in this heat exchange core section 26 a, the air is heated.

The heating heat exchanger 26 in this example is a so-called full-pass type heat exchanger that has, at its top and bottom ends, tank sections 26 b for distributing or collecting the hot water into/from the plurality of tubes, wherein the tank section at the bottom end constitutes a hot water inlet tank section.

A plate-like air mix door 27 is disposed above the heating heat exchanger 26 and a rotational axis 27 a of the air mix door 27 is disposed near the top end of the heating heat exchanger 26.

The rotational axis 27 a of the air mix door 27 is disposed so as to extend in the vertical direction with respect to the drawing plane of FIG. 3 (in the vehicle width direction) and both ends of the rotational axis 27 a are rotatably held by bearing holes (not shown) in the left and right side walls of the case 21. One end of the rotational axis 27 a protrudes outside the case 21 to be coupled to a driving mechanism (not shown).

Inside the case 21, at the air flow downstream of the cooling heat exchanger 24 and above the heating heat exchanger 26, there is formed a cool air bypass passage 28 that allows the cool air to bypass the heating heat exchanger 26 and flow as indicated by arrow b. On the other hand, inside the case 21, at the air flow downstream of the heating heat exchanger 26 (forward of the vehicle), there is formed a warm air passage 29 through which the warm air heated in the heating heat exchanger 26 flows as indicated by arrow c.

In a region at the vehicle forward of the heating heat exchanger 26, a warm air guide wall 31 that protrudes from the bottom surface 21 b of the case 21 is formed integrally with the case 21. This warm air guide wall 31 delimits a space at the vehicle forward of the warm air passage 29 and guides the warm air flow in the warm air passage 29 toward the cool air bypass passage 28, as indicated by arrow c.

As a result, in a region above the warm air passage 29 and around a tip of the warm air guide wall 31, there is formed an air mixing section 32 that can satisfactorily mix the warm air and the cool air with each other.

In FIG. 3, a position of the air mix door 27 indicated by solid lines is a maximum cooling position where the air passage of the heating heat exchanger 26 is fully closed and the cool air bypass passage 28 is fully opened, and on the other hand, another position thereof indicated by chain double-dashed lines is a maximum heating position where the cool air bypass passage 28 is fully closed and the air passage of the heating heat exchanger 26 is fully opened.

As well known, the air mix door 27 is a temperature adjustment means for adjusting temperature of the air flowing into the cabin by adjusting the flow ratio between the warm air passing through the heating heat exchanger 26 (arrow c) and the cool air bypassing the heating heat exchanger 26 and passing through the cool air bypass passage 28 (arrow b). Then, the above-mentioned warm air (arrow c) and the above-mentioned cool air (arrow b) are mixed with each other in the air mixing section 32 so as to obtain the air of a desired temperature.

Inside the case 21, above the cool air bypass passage 28, there is formed a face/defroster passage 33 that communicates with the air mixing section 32. This face/defroster passage 33 is configured to extend from the vehicle forward to the vehicle rearward. A front face/defroster opening 34 is opened in a vehicle forward position on the side wall of the face/defroster passage 33. Further, a rear face/defroster opening 35 is opened in a vehicle rearward position on the top surface of the face/defroster passage 33.

The front face/defroster opening 34 is connected with a front face/defroster duct (not shown) that extends in the vehicle forward direction, so that the air is blown out toward the face of the operator and the front windshield 16 through a front face blowout and a defroster blowout at the downstream end of the front face/defroster duct.

In this connection, the front face blowout and the defroster blowout are provided with respective shutter mechanisms (not shown), so that the front face blowout and the defroster blowout can be opened and closed independently of each other by the shutter mechanisms. These shutter mechanisms are operated to be opened and closed manually by the operator.

The rear face opening 35 is connected to a rear face duct (not shown) that extends upward, so that the air is blown out toward the face of the operator through a rear face blowout at the downstream end of the rear face duct.

Inside the case 21, at the vehicle forward of the warm air passage 29, there is formed a foot passage 36 that communicates with the air mixing section 32. This foot passage 36 is configured to extend from the top side to the bottom side.

A foot opening 37 is opened in the front wall at the lower part of the foot passage 36. The foot opening 37 is connected to a foot duct (not shown) that extends in the vehicle forward direction, so that the air is blown out around the feet of the operator through a foot blowout at the downstream end of this foot duct.

At the vehicle forward of the air mixing section 32, there is disposed a plate-like blowout mode switching door 38 that switchably opens and closes the face/defroster passage 33 and the foot passage 36. A rotational axis 38 a of the blowout mode switching door 38 is disposed so as to extend in the vertical direction with respect to the drawing plane of FIG. 3 (in the vehicle width direction) and both ends of the rotational axis 38 a are rotatably held by bearing holes (not shown) in the left and right side walls of the case 21. One end of the rotational axis 38 a protrudes outside the case 21 to be coupled to a driving mechanism (not shown).

In FIG. 3, a position of the blowout mode switching door 38 indicated by solid lines is a position in a face/defroster mode where the foot passage 36 is fully closed and the face/defroster passage 33 is fully opened. In contrast to this, a position of the blowout mode switching door 38 indicated by chain double-dashed lines is a position in a foot mode where the foot passage 36 is fully opened and the face/defroster passage 33 is fully closed.

Further, a plate-like rear face door 39 opens and closes the rear face opening 35 so as to adjust the flow ratio between the air blown out from the front face blowout and the defroster blowout and the air blown out from the rear face blowout.

A rotational axis 39 a of the rear face door 39 is disposed so as to extend in the vertical direction with respect to the drawing plane of FIG. 3 (in the vehicle width direction) and both ends of the rotational axis 39 a are rotatably held by bearing holes (not shown) in the left and right side walls of the case 21. One end of the rotational axis 39 a protrudes outside the case 21 to be coupled to a driving mechanism (not shown).

In FIG. 3, a position of the rear face door 39 indicated by solid lines is a position mode where the rear face opening 35 is fully opened. In contrast to this, a position of rear face door 39 indicated by chain double-dashed lines is a position where the rear face opening 35 is fully closed.

In this example, electric actuators comprising servo motors (not shown) are used as the driving mechanisms for rotating the air mix door 27, the blowout mode switching door 38 and the rear face door 39. Alternatively, as the driving mechanisms for these doors 27, 38 and 39, it may be possible to use manual operation mechanisms for transferring manual operating force of operation members (for example, manual operation levers) provided on the air conditioner operation panel (not shown) via cables, link mechanisms and the like.

Though not shown in the figures, the air conditioner operation panel is provided in a dashboard disposed in a forward region of the interior-cabin space 15 and has a refrigeration cycle compressor operation switch and an air flow rate switch, as well as a temperature setting switch, a blowout mode switching switch, a front/rear air flow ratio adjustment switch, an inside air/outside air mode switching switch and the like.

When the compressor operation switch on the air conditioner operation panel is turned on, the electromagnetic clutch of the refrigeration cycle compressor is energized and engaged and, therefore, the compressor is driven by the engine. As a result, in the cooling heat exchanger 24, the cold low-pressure refrigerant in the refrigeration cycle absorbs heat from the air and evaporates so as to cool the air.

Then, according to the temperature set by the temperature setting switch, the air mix door 27 is operated to adjust the temperature of the conditioned air flow.

Further, according to the setting of the blowout mode switching switch, the blowout mode switching door 38 is operated to switch the blowout mode, and according to the setting of the front/rear air flow ratio adjustment switch, the rear face door 39 is operated to adjust the air flow ratio between the front face blowout and the rear face blowout. Still further, according to the setting of the inside air/outside air mode switching switch, the outside air door and the inside air door are operated to switch the inside air/outside air mode.

In this connection, on the rear wall section 21 a of the case 21, a case side opening 40 that is provided facing the vehicle rearward direction. This case side opening 40 is provided for inspecting and cleaning the heat exchange core section 24 a of the cooling heat exchanger 24 and configured to be rectangular in this example.

In this example, the cooling heat exchanger 24 is disposed substantially vertically, and therefore, the heat exchange core section 24 a of the cooling heat exchanger 24 faces the case side opening 40. More specifically, an air flow upstream portion of the heat exchange core section 24 a of the cooling heat exchanger 24 faces the case side opening 40.

The case side opening 40 can be opened and closed by a case side cover 41. This case side cover 41 is molded of a resin material that has elasticity to some extent and excellent strength, such as polypropylene, similarly to the case 21.

The case side cover 41 is disposed outside the case 21 (in the vehicle rearward direction) with respect to the case side opening 40 and removably attached to the case 21 by fastening means such as screws, clips and the like (not shown). The case side opening 40 is opened and closed when the case side cover 41 is attached and removed, respectively.

An area of the case side cover 41 is smaller than an opening area of a cabin side opening 42 that is provided in the rear wall section 12 of the cabin 10. This cabin side opening 42 is provided facing the vehicle rearward direction, and at the same time, it overlaps the case side opening 40. In this example, the cabin side opening 42 is formed by rectangularly cutting out an outside sheet of the vehicle (a steel sheet in this example) in the rear wall section 12.

The cabin side opening 42 can be opened and closed by a cabin side cover 43. Though this cabin side cover 43 is formed by the steel sheet that is similar to the outside sheet of the vehicle, it may be formed of a resin material and the like.

The cabin side cover 43 is disposed outside (rearward) the cabin 10 with respect to the cabin side opening 42 and removably attached to the rear wall section 12 of the cabin 10 by fastening means such as screws, clips and the like (not shown). The cabin side opening 42 is opened and closed when the cabin side cover 43 is attached and removed, respectively.

Next, in the above configuration, a procedure for inspecting and cleaning the heat exchange core section 24 a of the cooling heat exchanger 24 will be described. First, the cabin side cover 43 is removed from the rear wall section 12 of the cabin 10 to the rearward of the cabin 10 to open the cabin side opening 42.

Since the cabin side cover 43 is disposed outside (rearward) the cabin 10 with respect to the cabin side opening 42, the cabin side cover 43 can be removed from the outside (rearward) of the cabin 10.

Next, the case side cover 41 is removed from the case 21 to the outside of the case (to the rearward of the vehicle) to open the case side opening 40.

Since the case side opening 40 overlaps the cabin side opening 42 and the case side cover 41 is disposed outside the case 21 (in the vehicle rearward direction) with respect to the case side opening 40, the case side cover 41 can be removed from the outside (rearward) of the cabin 10 through the cabin side opening 42.

Further, because the area of the case side cover 41 is smaller than the opening area of the cabin side opening 42, the removed case side cover 41 can be taken out to the outside of the cabin 10 through the cabin side opening 42.

As described above, by opening the case side opening 40 and the cabin side opening 42, the heat exchange core section 24 a of the cooling heat exchanger 24 is exposed to the outside of the cabin 10 and, therefore, the heat exchange core section 24 a of the cooling heat exchanger 24 can be inspected and cleaned from the outside of the cabin 10 (from the rearward of the cabin 10) through the cabin side opening 42 and the case side opening 40.

Then, after the heat exchange core section 24 a of the cooling heat exchanger 24 is inspected and cleaned, the case side cover 41 and the cabin side cover 43 are attached in the procedure reverse to that for removal described above.

In a construction machine such as a hydraulic excavator, which is used in a sandy and dusty environment etc., the heat exchange core section 24 a of the cooling heat exchanger 24 may become clogged due to dust adhering to the clearance between the fins of the core section. However, in this embodiment, the heat exchange core section 24 a of the cooling heat exchanger 24 can be inspected and cleaned from the outside of the cabin 10 (from the rearward of the cabin 10) while the cooling heat exchanger 24 remains accommodated in the case 21.

Therefore, in contrast to the vehicle air conditioner in Japanese Unexamined Utility Model Publication No. H05-56516 mentioned above, when the cooling heat exchanger 24 is inspected and cleaned, the cooling heat exchanger 24 does not have to be taken out from the case 21 of the air conditioning unit 20 and it does not have to be inspected and cleaned in the narrow cabin 10. As a result, the cooling heat exchanger 24 can be inspected and easily cleaned in a short period of time.

Further, in this embodiment, in which the air flow upstream portion of the heat exchange core section 24 a of the cooling heat exchanger 24 is oriented toward the case side opening 40 and the cabin side opening 42, the air flow upstream portion of the heat exchange core section 24 a that is more likely to be covered with the dust can be inspected and easily cleaned in a short period of time.

Still further, in this embodiment, as indicated by arrow a in FIG. 3, the air passing through the cooling heat exchanger 24 flows from the vehicle rearward to the vehicle forward. On the other hand, as indicated by arrow d in FIG. 3, the air passing through the fool opening 37 also flows from the vehicle rearward to the vehicle forward.

Thus, the flow direction of the air in the foot opening 37 coincides with that of the air passing through the cooling heat exchanger 24. Therefore, the flow rate of the air passing through the foot opening 37, and thus, the flow rate of the air blown out from the foot blowout can be ensured easily.

Still further, in this embodiment, in which the air outlet section 22 e of the blower section 22 can be disposed at the rearmost position of the air conditioning unit 20 as can be seen from FIG. 2A, the air outlet section 22 e of the blower section 22 can be kept far from the operator. Therefore, air blow noise heard by the operator can be reduced.

Still further, in this embodiment, in which the substantially rectangular-shaped cooling heat exchanger 24 is disposed substantially vertically inside the case 21, the dimensions of the air conditioning unit 20 in the front and rear direction of the vehicle can be reduced. As a result, the space available for the operator in the interior-cabin space 15 can be extended.

As a reference example, the air conditioning unit 20 may be configured reversely in the front and rear direction to that of this embodiment, so that the case side opening 40 is opened toward the seat 18 (in the vehicle forward direction). Alternatively, as another reference example, the case side opening 40 may be formed in the top surface section of the case 21 or, more specifically, in a region above the inflow space 25 of the top surface section of the case 21.

In these reference examples, though the cooling heat exchanger 24 cannot be inspected and cleaned from the outside (rearward) of the cabin 10 and it has to be inspected and cleaned inside the cabin 10, the cabin side opening 42 and the cabin side cover 43 can be omitted.

Second Embodiment

In contrast to the first embodiment described above, in which the case side opening 40 is opened and closed by removing and attaching the case side cover 41 from/to the case 21 and the cabin side opening 42 is opened and closed by removing and attaching the cabin side cover 43 from/to the rear wall section 12 of the cabin 10, in this second embodiment, as shown in FIG. 4, the both opening 40 and 42 are opened and closed by swinging the both covers 41 and 43 in a direction orthogonal to the opening direction of the opening 40 and 42 (the front and rear direction of the vehicle in this example).

More specifically, a top edge section of the case side cover 41 is secured to the case 21 via a hinge (not shown) and a top edge section of the cabin side cover 43 is secured to the rear wall section 12 of the cabin 10 via a hinge (not shown). Therefore, the covers 41 and 43 are held swingably in the vertical direction, so that the opening 40 and 42 can be easily opened and closed by the covers 41 and 43.

Further, when the case side cover 41 is swung in the direction to open the case side opening 40, the case side cover 41 protrudes to the outside of the cabin 10 through the cabin side opening 42. Therefore, the case side opening 40 can be opened completely.

In this connection, though the hinges disposed at the top edge sections of the covers 41 and 43 in this example, the hinges may be disposed at the bottom edge sections of the covers 41 and 43. Further alternatively, the hinges may be disposed at right or left edge sections of the covers 41 and 43, so that the covers 41 and 43 can be held swingably in the horizontal direction.

Third Embodiment

In contrast to the second embodiment described above, in which the opening 40 and 42 are opened by swinging the covers 41 and 43, in this third embodiment, as shown in FIG. 5, the both opening 40 and 42 are opened and closed by shifting (sliding) the covers 41 and 43 in a direction orthogonal to the opening direction of the opening 40 and 42 (the front and rear direction of the vehicle in this example).

More specifically, left and right edge sections of the case side cover 41 are secured to the case 21 via slide mechanisms (not shown) and the left and right edge sections of the cabin side cover 43 are secured to the rear wall section 12 via slide mechanisms (not shown).

Therefore, the covers 41 and 43 are held slidably in the vertical direction. Here, the lower part of the rear wall section 12 of the cabin 10 extends in the vertical direction and therefore, the case side cover 41 can be shifted in the interior-cabin space 15 without interference with the rear wall section 12.

As described above, the opening 40 and 42 can be opened and closed by sliding the covers 41 and 43 in the vertical direction.

In this connection, though the covers 41 and 43 are held slidably in the vertical direction, the covers 41 and 43 may be held slidably in the horizontal direction.

Other Embodiments

Though the air conditioning unit 20 is disposed at the rearmost and lowermost position of the interior-cabin space 15 in the embodiments described above, the disposing position of the air conditioning unit 20 is not limited to this position. For example, the air conditioning unit 20 may be disposed at the lowermost position in the center of the interior-cabin space 15 or, in other words, under the seat 18.

In this case, the air conditioning unit 20 may be disposed in an orientation horizontally rotated by 90 degrees from that in the embodiments described above so that the heat exchange core section 24 a of the cooling heat exchanger 24 faces the side wall section of the cabin 10, and the cabin side opening 42 and the cabin side cover 43 may be disposed at the side wall section of the cabin 10.

Further, though the cooling heat exchanger 24 and the heating heat exchanger 26 are provided as heat exchangers for exchanging heat with air in the embodiments described above, the cooling heat exchanger 24 may be omitted and only the heating heat exchanger 26 may be provided.

In this case, a heat exchange core section 24 a of the heating heat exchanger 26 may be disposed to face the case side opening 40. As a result, the heating heat exchanger 26 can be inspected and easily cleaned in a short period of time.

Still further, though the air flow upstream portion of the heat exchange core section 24 a of the cooling heat exchanger 24 faces the case side opening 40 in the embodiments described above, an air flow downstream portion of the heat exchange core section 24 a may face the case side opening 40.

Though the embodiments described above show examples in which the vehicle air conditioner according to the present invention is applied to the construction machine such as the hydraulic excavator and the like, the present invention may be applied not only to a construction machine such as a hydraulic excavator and the like, but also to other various vehicles. For example, the present invention may be applied to an agricultural tractor, etc.

While the invention has been described with reference to specific embodiments chosen for purposes of illustration, it should be apparent that numerous modifications could be made thereto by those skilled in the art without departing from the basic concept and scope of the invention. 

1. A vehicle air conditioner comprising: a case that is disposed in an interior-cabin space formed in a cabin and that forms an air passage through which air flows; and a heat exchanger that is accommodated in said case and that exchanges heat with the air, wherein said case is disposed adjacent to a surrounding wall section of said cabin, a case side opening that is opened and closed by a case side cover in a region of said case adjacent to said surrounding wall section, said case side opening overlaps a cabin side opening that is provided in said surrounding wall section and that is opened and closed by a cabin side cover, and a heat exchange core section of said heat exchanger faces said case side opening.
 2. A vehicle air conditioner according to claim 1, wherein an air flow upstream portion of said heat exchange core section faces said case side opening.
 3. A vehicle air conditioner according to claim 1, wherein said surrounding wall section is a rear wall section of said cabin, said case is disposed rearward in said cabin, and said heat exchanger is disposed rearward in said case.
 4. A vehicle air conditioner according to claim 1, wherein an area of said case side cover is smaller than that of said cabin side opening, said case side cover is removably attached to said case, and said case side opening is opened and closed when said case side cover is attached and removed, respectively.
 5. A vehicle air conditioner according to claim 1, wherein an area of said case side cover is smaller than that of said cabin side opening, said case side cover is swingably supported with respect to said case in a direction orthogonal to the opening direction of said case side opening, said case side opening is opened and closed by swinging said case side cover, and, further, when said case side cover is swung in a direction to open said case side opening, said case side cover protrudes to the outside of said cabin through said cabin side opening.
 6. A vehicle air conditioner according to claim 1, wherein said case side cover is supported and can be shifted with respect to said case in a direction orthogonal to the opening direction of said case side opening, said case side opening is opened and closed by translating said case side cover, and, further, said case side cover is shifted in said interior-cabin space (15). 